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茶多糖（Tea polysaccharide (TPS) is the second most abundant ingredient in tea following tea polyphenols. As a complex polysaccharide, TPS has a complex chemical structure and a variety of bioactivities, such as anti-oxidation, hypoglycemia, hypolipidemic, immune regulation, and anti-tumor. Additionally, it shows excellent development and application prospects in food, cosmetics, and medical and health care products. PS）是茶叶中仅次于茶多酚的第二丰富成分。作为一种复合多糖，TPS具有复杂的化学结构和多种生物活性，如抗氧化、降血糖、降血脂、免疫调节、抗肿瘤等。此外，在食品、化妆品、医药保健品等方面也显示出良好的开发和应用前景。茶叶、花和种子是茶多糖提取材料的三大主要来源。TPS的生产工艺主要有热水提取、超声波辅助提取、微波辅助提取、酶解提取等。
- tea
- polysaccharides
- extraction method
1. Introduction一、简介
As a traditional drink, tea has been cultivated and consumed for thousands of years, and it is deeply loved by consumers from many countries, such as China, Japan, and South Korea. 目前Tea not only creates a lot of wealth but also generates tea culture and tea ceremony [1]. As a result, tea has become one of the most popular beverages in the world after water [2][3][4].
The unprecedented popularity of tea is due not only to its unique aroma and taste but also to the health benefits of drinking it. The primary bioactivities of tea, including anti-oxidation, hypoglycemic, antibacterial, hypolipidemic, and anti-cancer activities, have been studied and explored. Tea has also been broadly utilized in the food, medical, and health care industries [5][6]. Tea’s biological and pharmacological activities are mainly attributed to the diversity of its chemical components. The chemical features of tea mainly include tea polyphenols (TPPs), tea polysaccharides (TPSs), tea proteins, catechins, theanine, and inorganic elements [4]. Tea polyphenols have long received attention for their excellent antioxidant properties for which accumulating evidence has been presented [7]. Modern pharmacological studies have shown that TPS, an important bioactive component along with TPP, is also the main tea compound that helps lower blood glucose and lipids, resist oxidation, and enhance the body’s immune function [8][9][10]. It also has excellent potential for development and application in the cosmetic industry [11]. In general, the content of TPS decreases with increases in tea quality or grade [12]. Wang et al., reported that the TPS content in low-grade tea was twice that of high-grade tea [13]. Therefore, using low-grade tea as a raw material to extract TPS is conducive to the full utilization of tea resources and has important implication for preventing diseases and promoting human health.
It was conducted that a detailed comparison and summary of the current research on tea polysaccharide’s extraction, preliminary physicochemical properties, and in vitro and in vivo bioactivities in order to provide new insights for the better utilization and development of TPS or TPS-related functional foods.
2. TPS Extraction
Tea leaves, flowers, and seeds are the three primary sources of TPS extraction materials. The current production process of TPS mainly includes hot water extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and enzymolysis extraction (Table 的生产工艺主要有热水提取、超声波辅助提取、微波辅助提取、酶解提取（表1). Its conventional preparation process is shown in Figure ）。其常规制备工艺如图1.所示。
Figure图 1. The conventional process of TPS preparation.
TPS 制备的常规过程。
Table表 1. Comparison of extraction methods of tea polysaccharide (TPS).
茶多糖（TPS）提取方法比较
| Extraction Method提取方法 | TPS Origin起源 | Extraction Step提取步骤 | Ref参考 |
|---|---|---|---|
| Hot water extraction热水提取 | Green tea leaves and flowers绿茶叶和花 | Pre-extraction with 95% ethanol at 40 °C for 2 h, repeated three times; a water bath extraction at 60 °C for 2 h, repeated 3 times乙醇40℃预提取2 h，重复3次；60℃水浴萃取2小时，重复3次 | [14][ 14 ] |
| Fuan Baicha and Pingyang Tezaocha福安白茶、平阳特早茶 | Extraction at 80 °C for萃取 1.5 h, repeated two times，重复 2 次 | [15][ 15 ] | |
| Fuzhuan tea茯砖茶 | 提取时间2 h extraction time, 1:20 solid–liquid ratio, and 95 °C extraction temperature; repeated three times，料液比1:20，提取温度95 ℃；重复三遍 | [10][ 10 ] | |
| White tea白茶 | 提取时间8 min extraction time, 54.1 °C extraction temperature, ，提取温度54.1 ℃，料水比12.48 L/g material–water ratio; repeated four times；重复四次 | [16][ 16 ] | |
| Green tea绿茶 | Heating in a water bath在 at 90 °C for 2 h with continuous stirring90°C 的水浴中加热 2 小时并持续搅拌 | [17][ 17 ] | |
| Green tea绿茶 | Pre-extraction with absolute ethanol for无水乙醇预萃取 24 h and extraction with deionized water at ，去离子水 60 °C for萃取 90 min | [18][ 18 ] | |
| Chin brick tea钦砖茶 | 80% ethanol乙醇预处理并用蒸馏水 pretreatment and continuous stirring with distilled water (1:20, w / v ) at在 90 °C for下连续搅拌 2 h | [19][ 19 ] | |
| Liupao tea六泡茶 | 80% ethanol pretreatment for 乙醇预处理24 h and extraction with deionized water at 70 °C for 2 h; repeated three times，去离子水70℃萃取2 h；重复三遍 | [20][ 20 ] | |
| Tea flowers茶花 | Extraction at 90 °C for 1 h (2 times)萃取 1 小时（2 次） | [21][ 21 ] | |
| Green tea绿茶 | 80% ethanol pretreatment at 乙醇70 °C for 1.5 h, extraction with ethanol at 40 °C for 3 h℃预处理1.5小时，40℃乙醇提取3小时 | [22][ 22 ] | |
| Green tea绿茶 | Pretreatment with two times volume of 2倍体积95% ethanol at 50 °C for 4 h, 1:8 solid–liquid ratio, and extraction with stirring at 50 °C for 120 乙醇50℃预处理4h，料液比1:8，50℃搅拌萃取120min | [23][ 23 ] | |
| Green tea绿茶 | Pretreatment用 with 95% alcohol (1:5, 95% 酒精（1:5，w / v) for 2 h, extraction in hot water (1:10,）预处理 2 小时，在 80°C的热水（1:10， w / v) at 80 °C; repeated ）中萃取；重复3 times for 次，每次1 h each time小时 | [24][ 24 ] | |
| Green tea绿茶 | 95% ethanol (乙醇（1:6, ，w / v)）在 pretreatment at 60 °C for 4 h and extraction with distilled water (1:10, 60°C 预处理 4 小时，用蒸馏水（1:10，w / v)）在 at 80 °C for 4 h; repeated 3 times80°C 提取 4 小时；重复3次 | [25][ 25 ] | |
| Keemun black tea祁门红茶 | Pretreatment用 with 95% ethanol (1:6, 95% 乙醇（1:6，w / v)）在 at 80 °C for 2 h and immersed in distilled water (1:10, 80°C 预处理 2h，然后浸入 80°C 蒸馏水（1:10，w / v)）中 at 80 °C for 4 h; repeated four times4h；重复四次 | [26][ 26 ] | |
| Ultrasonic-assisted extraction超声辅助提取 | Low-grade green tea低档绿茶 | 提取温度 80 °C extraction temperature, ，提取时间 60 min extraction time, 400 W ultrasonic power, and ，超声波功率 400 W，液固比 22 mL:g liquid–solid ratio | [27][ 27 ] |
| Coarse tea粗茶 | Pretreatment in an ultrasonic bath (在超声波浴（50 °C, 200 W) for 30 min followed by extraction in a water bath for 90 min; repeated three times，200 W）中预处理 30 分钟，然后在水浴中提取 90 分钟；重复三遍 | [23][ 23 ] | |
| Green tea flowers绿茶花 | Ultrasonic power (超声波功率（25 °C, 100, 150, 200, 250, and、100、150、200、250 和 300 W) extraction for 5 min; repeated 2 times）萃取 5 分钟；重复2次 | [21][ 21 ] | |
| Yellow tea黄茶 | 95% ethanol pretreatment for乙醇预处理 6 h, ，90 °C water bath extraction for 水浴萃取 55 min (repeated twice), and sonication (（重复两次），超声处理（20 kHz, 500 W) for ，500 W）55 min | [21][ 21 ] | |
| Microwave-assisted extraction微波辅助萃取 | Green, black, and oolong teas绿茶、红茶和乌龙茶 | 1:20 solid/liquid ratio, 固液比，200–230 °C extraction temperature, and 2 min extraction time提取温度，2 分钟提取时间 | [28][ 28 ] |
| Green tea flowers绿茶花 | Extraction在受控微波功率下萃取 at controlled microwave power for 5 min followed by extraction with distilled water for 5 min at the same microwave power5 分钟，然后在相同微波功率下用蒸馏水萃取 5 分钟 | [21][ 21 ] | |
| Green tea绿茶 | Extraction in a 600 W microwave apparatus for 30 min, followed by stirring in a water bath for 90 min; repeated three timesW微波仪器萃取30min，水浴搅拌90min；重复三遍 | [29][ 29 ] | |
| Enzymolysis extraction酶解提取 | Green tea绿茶 | Extraction at 100 °C for 3 h and aqueous extraction with pectinase and tannase at 35 °C for 2 h℃萃取3小时，果胶酶和鞣酸酶水萃取35℃2小时 | [30][ 30 ] |
| Green tea绿茶 | Extraction用复合酶（纤维素酶：果胶酶：葡聚糖酶 with complex enzymes (cellulase:pectinase:glucanase = 1:1:2) at 50 °C for 30 min, boiling at 90 °C for 10 min, and then extraction in a water bath at 50 °C for 80 min）在 50°C 提取 30 分钟，在 90°C 沸腾 10 分钟，然后在 50°C 水浴中提取 80 分钟 | [29][ 29 ] | |
| Green tea leaves and flowers绿茶叶和花 | 95% ethanol pretreatment at 乙醇40 °C for 2 h (repeated 3 times), treatment with 0.5% (m/v) pentosan complex enzyme solution (45 °C, ℃预处理2h（重复3次），0.5%（m/v）戊聚糖复合酶溶液（45℃，pH 5.5) for 2 h, and extraction in 45 °C water bath for 2 h）处理2h，45℃水浴萃取2小时 | [14][ 14 ] | |
| Green tea绿茶 | Heating in a water bath at 在90 °C for 2–4 h, repeated twice; incubating with 0.5% pectinase℃水浴中加热2-4小时，重复两次；与 0.5% 果胶酶 (260,001 PGU/mL, v / w ) at在 40 °C for 30 min; and heating at 90 °C for 1 h to inactivate the enzyme下孵育 30 分钟；并在 90°C 下加热 1 小时以使酶失活 | [31][ 31 ] | |
| Hydro水/solvothermal extraction溶剂热萃取 | Chinese tea Zhongcha 中国茶中茶108 | Extraction at 120 °C for 1 h萃取 1 小时 | [1][ 1 ] |
| Alkali-assisted extraction碱辅助萃取 | Fuzhuan brick tea福砖砖茶 | Extraction在 60 °C with下用 0.1 M NaOH solution溶液 (pH = 10.0) at 60 °C, repeated 3 times萃取，重复 3 次 | [32][ 32 ] |
| Supercritical fluid extraction超临界流体萃取 | Green tea绿茶 | 380 μm particle size, 粒径，20% absolute ethanol, 无水乙醇，35 MPa extraction pressure, 提取压力，45 °C extraction temperature, and 2 h extraction time提取温度，2 h 提取时间 | [33][ 33 ] |
| Anionic reverse micelle extraction阴离子反胶束萃取 | Green tea绿茶 | pH = 4.6, 、0.06 M guanidine hydrochloride, 7% methanol, and 盐酸胍、7% 甲醇和 0.05 M NaCl; forward extraction；前向提取 | [34][ 34 ] |
2.1. Hot Water Extraction
Most
2.热水提取
大多数生物活性多糖是极性的，因此通常使用热水或碱性溶液等极性溶剂提取多糖 bioactive[ polysaccharides33 are]。热水提取是食品、医药等行业广泛用于制备多糖的经典方法[ polar,34 so polar solvents such as hot water or alkaline solutions are usually used for polysaccharide extraction [33]. Hot water extraction is a classic method widely used to prepare polysaccharides in food, medicine, and other industries [34]. ]。Chen et al., used water bath heating (等人使用水浴加热（70 °C, 60 min) to extract three kinds of crude TPSs from℃，60 分钟）从黑茶、乌龙茶和绿茶叶中提取三种粗制 TPS [ black,35 oolong, and green tea leaves [35]. ]。Xu et al., prepared等人在 TPS from Pu-erh tea three times for 180 min in hot water at 70 70°C [36].的热水中用 Fan3 et al., extracted TPS twice in Fuan次普洱茶制备 TPS，每次 180 分钟 [ Baicha36 and]。范等人在福安白茶和平阳特早茶中加入双蒸水，在 Pingyang Tezaocha by adding double-distilled water and heating in a water bath at 80 °C for 1.5 h80 ℃水浴中加热 1.5 小时，两次提取 [37].TPS Zhu[ et al., used the response surface methodology to explore the extraction process of Fuzhuan tea crude polysaccharide (37]。朱等人利用响应面法对茯砖茶粗多糖（CDTPS) and found that the optimal extraction conditions (repeated four times) were as follows: an extraction time of ）的提取工艺进行了探索，发现最佳提取条件（重复4次）为：提取时间为2 h, a solid–liquid ratio of 1:20, and an extraction temperature of 95 °C. Under these conditions, the yield of ，固液比例为 1:20，萃取温度为 95 °C。在此条件下，CDTPS was的收率为 6.07% [10].[ The10 response surface methodology used by ]。Jin et al., predicted the optimal extraction conditions of TPS via repetition four times in white tea: the optimal extraction time was 等人采用响应面法，通过重复4次在白茶中预测TPS的最佳提取条件：最佳提取时间为97.8 min, the extraction temperature was 54.1 °C, and the material–water ratio was 12.48 L/g，提取温度为54.1 ℃，料水比为12.48升/克 [14].[ 14]。Wang et等人将干燥的绿茶叶和花在 al., pretreated dried green tea leaves and flowers in 95% ethanol and 40 °C for 2 h, then repeated the process three times to remove pigments and other substances. Then, 2 L of distilled water was added to the filtered tea samples for extraction in a water bath at 60 °C for 2 h. After filtration, 95% 乙醇和 40°C 中预处理 2 小时，然后重复该过程 3 次以去除色素和其他物质。然后，将 2 L 蒸馏水加入过滤后的茶样品中，在 60 ℃水浴中提取 2 h。过滤后，加入 2.5 L of distilled water was added, and the hot water extraction was repeated again (60 °C, 2 h)蒸馏水，再次重复热水萃取（60 ℃，2 h）[ [38].38 Similarly, ]。类似地，Cai et al., pretreated green tea leaves with absolute ethanol for 24 h to remove some small-molecular pigments and polyphenols, and then they dried the tea samples with deionized water for 90 min at 60 等人用无水乙醇预处理绿茶叶 24 小时以去除一些小分子色素和多酚，然后用去离子水在 60°C [16].下将茶叶样品干燥 Li90 et al.,分钟 [ also16 pretreated Ch]。Lin brick tea powder with 80% ethanol, centrifuged it, and then continuously stirred it with distilled water (1:20, 等人也用 80% 乙醇预处理了金砖茶粉，离心后用蒸馏水（1:20，w/ v ) for 2 h at 在 90 °C to extract下 2 小时以提取 TPS [17].[ Qin17 et]。秦等人用 al., pretreated Liupao tea samples with 80% ethanol for 24 h. After filtration and drying, the samples were extracted with deionized water at 70 °C for 2 h, and the process80% 乙醇预处理六泡茶样品 24 小时。过滤和干燥后，样品用去离子水在 70°C 下萃取 2 小时，该过程重复 3 次 [ was18 repeated three times [18]. ]。Wei et al., performed the hot water等人对干茶花多糖 extraction of dried tea flower polysaccharides (TFPSs) and then extracted TFPSs twice with distilled water (1 h each). They found that the yield of TFPS increased with the extraction temperature, and 90 °C was the optimal extraction temperature for TFPS. The yield at this condition was close to (TFPS) 进行热水提取，然后用蒸馏水提取 TFPS 两次（每次 1 小时）。他们发现TFPS的得率随着提取温度的增加而增加，90℃是TFPS的最佳提取温度。此条件下的收率接近 35% [19].[ 19]。虽然热水提取是Though hot water extraction is a commonly used method for TPS提取的常用方法，但传统的热水提取存在提取效率低、提取时间长、提取温度高等缺点，限制了其可用性[ extraction,33、39 conventional hot water extraction has disadvantages such as a low extraction efficiency, long extraction time, and high extraction temperature, all of which limit its availability [33][39]. For example, ]。例如，Wang et al., further compared等人进一步比较了 the yields of hot water extraction, boiling water extraction, and enzymolysis extraction for TFPS, and they found that the yield of TFPS obtained with enzymolysis extraction was the highest (2.01%), followed by boiling water extraction TFPS 的热水提取、沸水提取和酶解提取的得率，他们发现酶解提取的 TFPS 的得率最高（2.01%），其次是煮沸。水萃取 (1.91%) and finally hot water extraction ，最后是热水萃取 (1.83%) [20].[ Zhu et al., compared the yields of crude green tea polysaccharides (CTPSs) under hot water extraction (20]。朱等人比较了热水提取（WE), enzymatic extraction (）、酶促提取（EE), microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE), and they found that the four yields of CTPS under these extraction methods were）、微波辅助提取（MAE）和超声辅助提取（UAE）三种粗绿茶多糖（CTPSs）的得率，他们发现：这些提取方法下 CTPS 的四种收率分别为 3.98%, 4.17%, 4.31%, and、4.17%、4.31% 和 4.52%, respectively [ [21]. Numerous studies have verified that although hot water extraction has strong practicability, its obtained 21]。大量研究证实，虽然热水提取具有很强的实用性，但其获得的TPS yield is relatively low收率较低，容易造成不必要的原料浪费。因此，许多研究人员还在热水提取的基础上改进了该技术，并开发了其他辅助提取方法，如超声波辅助提取、微波辅助提取、酶辅助提取等，以提高 and easily leads to the unnecessary waste of raw materials. Therefore, many researchers have also improved the technology on the basis of hot water extraction and developed other auxiliary extraction methods, such as ultrasonic-assisted extraction, microwave-assisted extraction, and enzyme-assisted extraction, to improve the extraction efficiency of TTPS [40].
2.2. Ultrasonic-Assisted Extraction (UAE)
UAE的提取效率 can[ accelerate40 the rupture of plant cell walls by the high-speed movement of molecules in samples caused by high-frequency ultrasonic vibration, thereby dissolving and releasing intracellular substances. ]。
3. 超声波辅助萃取 (UAE)
阿拉伯联合酋长国可以通过高频超声振动引起的样品中分子的高速运动，加速植物细胞壁的破裂，从而溶解和释放细胞内物质。Karadag et等人利用阿联酋提取低品位绿茶多糖 al., used UAE to extract low-grade green tea polysaccharides (GTPSs) and then reported the optimal extraction parameters through response surface optimization as follows: 80 °C for extraction temperature, 60 min for extraction time, ，然后通过响应面优化报告了最佳提取参数如下：提取温度 80 ℃，提取时间 60 分钟，超声波功率 400 W for ultrasonic power, and, 和 22 mL/g for liquid–solid ratio. Under these conditions, the yield of GTPS was的液固比。在此条件下，GTPS 的收率为 4.65%, which was higher than that of the hot water extraction method (1.83%)，高于无超声波的热水提取法（1.83%）[ without25]。此外，他们还发现，超声辅助提取得到的 ultrasound [25]. In addition, they also found that the Mw of GTPS obtained的 with ultrasonic-assisted extraction was lower, which may have been due to the partial degradation of TPS caused by the ultrasonic process. Zhu et al., prepared TPS from coarse green tea leaves, placing the tea leaves in an ultrasonic bath (50 °C, 200 W) for pretreatment for 30 min and then performing extraction in a water bath for 90 min. The TPS yield obtainedMw 较低，这可能是由于超声过程导致 TPS 部分降解所致。朱等人用粗绿茶叶制备TPS，将茶叶置于超声波浴（50℃，200W）中预处理30分钟，然后在水浴中提取90分钟。用这种方法获得的 TPS 产量高于其他测试方法 [ with21]。为了探索超声对黄茶多糖 this method was higher than other tested methods [21]. To explore the effects of ultrasound on the structure and activity of yellow tea polysaccharide (YTPS), Wang et al., treated a YTPS fraction obtained after hot water extraction and deproteinization with ultrasound 结构和活性的影响，Wang 等人用超声 (20 kHz, 500 W) for 55 min. The results showed that ultrasonic treatment basically did not change the main chemical composition of YTPS but did处理热水提取和脱蛋白后获得的 YTPS 馏分 55 分钟。结果表明，超声波处理基本没有改变 YTPS 的主要化学成分，但确实导致其降解 [ cause26 it to degrade [26]. ]。Wei et等人将干燥的绿茶花块与蒸馏水混合，在 al., mixed dried green tea flower blocks with distilled water and extracted them for 5 min at 25 °C under ultrasonic powers of 100, 150, 200, 250, and100、150、200、250 和 300 W. This process was repeated twice to obtain crude 的超声波功率下，在 25°C 下提取 5 分钟。此过程重复两次以获得粗 TFPS [19].[ Overall, the 19]。总体而言，UAE方法具有省时、操作简单、实验安全、成本低、提取率高等优点。尽管如此，它可能会降解可溶性 method has the advantages of saved time, simple operation, experimental safety, low cost, and high extraction rate. Still, it may degrade soluble TPS and affect its bioactivity.
2.3. Microwave-Assisted Extraction (MAE)
Recently, microwave-assisted extraction (TPS 并影响其生物活性。
4. 微波辅助萃取 (MAE)
近年来，微波辅助提取（MAE) technology has become widely used to analyze and extract active components in plants. ）技术已广泛用于分析和提取植物中的活性成分。MAE is a new extraction technology that uses high-frequency electromagnetic waves (0.3–是一种利用高频电磁波（0.3-300 GHZ)）具有强穿透性和加热效应的提取植物活性成分的新型提取技术。高能微波可以穿透溶剂和植物细胞壁，将能量传递到细胞质，并与极性成分相互作用产生热量，从而提高细胞内的温度和压力。当压力达到一定水平时，细胞壁膨胀破裂，释放出胞内多糖等物质[ with strong penetrability and heating effect to extract active plant components. High-energy microwaves can penetrate solvents and plant cell walls, transfer energy to the cytoplasm, and interact with polar components to generate heat, which increases the temperature and pressure inside cells. When the pressure reaches a certain level, the cell wall expands and ruptures, releasing intracellular polysaccharides and other substances [41]. 41]。Shuntaro et等人使用 al., used MAE technology to extract TPS from tea residues (green tea, black tea, and oolong tea). When the extraction conditions were a solid/liquid ratio of 1:20, an extraction temperature of 200–230 °C, and an extraction time of 2 min, the yield of tea residue TPS was 40–MAE 技术从茶渣（绿茶、红茶和乌龙茶）中提取 TPS。当提取条件为料液比为 1:20、提取温度为 200~230 ℃、提取时间为 2 min 时，茶渣 TPS 的得率为 40~50% [27].[ 27 ]。Wei et al., used MAE equipment to extract TFPS twice, for 5 min each time. They found that the yield of TFPS changed irregularly with the increase in microwave power. In addition, with increases in microwave power, the content of neutral sugars in TFPS increased while等人使用 MAE 设备提取 TFPS 两次，每次 5 分钟。他们发现，随着微波功率的增加，TFPS 的产量发生了不规则的变化。此外，随着微波功率的增加，TFPS 中中性糖的含量增加，而酸性糖的含量先增加后减少 [ the content of acidic sugars increased and then decreased [19]. 19]。Li et al., used a 等人使用600 W microwave instrument to extract coarse green tea crude TPS (CTPS), and the extraction process was repeated three times. After extraction with MAE, the content of soluble protein in CTPS was the highest of all tested methods, reaching 5.93%. Furthermore, they found that MAE treatment had little effect on CTPS chains with high Mw but resulted in the drastic degradation of small-Mw CTPS. According to related reports, small-Mw polysaccharides tend to have better bioactivities than their high-Mw counterparts [42]. The subsequent in vitro activity test of 微波仪器提取粗绿茶粗TPS（CTPS），提取过程重复3次。经MAE提取后，CTPS中可溶性蛋白的含量是所有测试方法中最高的，达到5.93%。此外，他们发现 MAE 处理对高 Mw 的 CTPS 链几乎没有影响，但会导致小 Mw CTPS prepared的急剧降解。根据相关报道，小分子量多糖往往比其高分子量多糖具有更好的生物活性[ by42 the]。随后朱等人用 MAE method by Zhu et al., also confirmed this conclusion [21]. 法制备的 ComparedTPS to other的体外活性试验，也证实了这一结论 [ extraction methods, the 21]。与其他提取方法相比，MAE method has the advantages of high extraction efficiency, high purity, non-degradable active ingredients, convenient operation, saved time, and environmental friendliness. It is a 法具有提取效率高、纯度高、活性成分不可降解、操作方便、省时、环保等优点。这是一种“green extraction process”, which has made it popular. Although MAE has favorable prospects in TPS绿色提取工艺”，使其广受欢迎。MAE虽然在TPS提取方面具有良好的前景，但也存在提取成分复杂、后期分离纯化困难、需要极性溶剂等缺点[ extraction,43 it]。因此，除了基本的封闭和开放系统外，还开发了真空微波辅助萃取、氮气保护微波辅助萃取、超声微波辅助萃取和动态微波辅助萃取等几种改进的微波萃取技术。 also[41 has disadvantages such as complex extract components, difficult separation and purification in the later stages, and the necessity of polar solvents [43]. ]。
5. 酶解提取
酶解法是指用酶水解破坏植物细胞壁。细胞壁分解成易溶于萃取溶剂的小分子物质，从而加速活性成分的溶解。酶解提取的Therefore, in addition to the basic closed and open systems, several improved microwave extraction technologies, such as vacuum microwave-assisted extraction, nitrogen-protected microwave-assisted extraction, ultrasonic microwave-assisted extraction, and dynamic microwave-assisted extraction, have been developed [41].
2.4. Enzymolysis Extraction
The enzymolysis method refers to the destruction of plant cell walls with enzymatic hydrolysis. The cell wall is decomposed into small molecular substances readily soluble in the extraction solvent, thereby accelerating the dissolution of active ingredients. The yield of TPS extracted with enzymatic hydrolysis is usually higher and the effect of mixed enzymes is better than that of a single enzyme. However, the enzyme’s activity is easily affected by the reaction tem的得率通常较高，混合酶的效果优于单一酶。但酶的活性易受反应温度、perature, pH, and concentration, so the requirements for experimental conditions and costs are usually higher. Baik et al., investigated the effect of the simultaneous treatment of pectinase and tannase on TPS extractionH、浓度等因素的影响，因此对实验条件和成本的要求通常较高。Baik 等人研究了果胶酶和鞣酸酶同时处理对绿茶中 TPS 提取的影响。28 from green tea. They found that the concurrent treatment of the two enzymes was an effective method for TPS extraction and could significantly improve TPS’s free radical scavenging activity [28]. ]。Chang et al., used pectinase-assisted extraction to obtain green tea 等人利用果胶酶辅助提取获得绿茶TPS, and the primary extraction process was as follows: the ground tea powder was heated in a water bath at 90 °C for 2–4 h, 0.5% pectinase (，初步提取工艺如下：将磨碎的茶粉在90°C的水浴中加热2-4小时，0.5%果胶酶（260,001 加入PGU/mL, v / w ) was added and incubated at 40 °C for 30 min, and then the enzyme was inactivated by heating at 90 °C for 1 h. The prepared TPS presented excellent并在 40°C 下孵育 30 分钟，然后通过在 90°C 下加热 1 小时使酶失活。制备的 TPS 具有出色的免疫刺激和对免疫细胞的保护作用 [ immune stimulation and protection against immune cells [30]. In addition to bioactivity, yield is also a concern for enzymolysis extraction. 30]。除了生物活性外，产率也是酶解提取的一个问题。Zhu et等人使用混合酶（纤维素酶：果胶酶：葡聚糖酶 al., used mixed enzymes (cellulase:pectinase:glucanase = 1:1:2) for crude green tea polysaccharide (CTPS) extraction at 50 °C (30 min), followed by boiling to inactivate the enzyme (10 min) and extracting in a water bath at 50 °C for 80 min. The whole process was repeated three times. The CTPS obtained with this method had a high total sugar content (）在 50 °C（30 分钟）下提取粗绿茶多糖（CTPS），然后煮沸使酶失活（10 分钟）并在 50°C 水浴中萃取 80 分钟。整个过程重复了三遍。用该方法获得的 CTPS 总糖含量较高（71.83%), which），这主要归因于混合酶对细胞壁的温和有效破坏 [ could21 mainly, be attributed to the gentle and efficient destruction of the cell walls by mixed enzymes [21][44]. 44]。Wang et等人使用 al., used a 0.5% (m/v) pentosan complex enzyme solution (45 °C, 戊聚糖复合酶溶液（45 °C，pH 5.5) to extract TPS from green tea leaves and flowers pretreated with 95% ethanol for 2 h. After filtration, the same extraction process at the same temperature was repeated. The yields of two TPSs obtained with this method were ）从用 95% 乙醇预处理 2 小时的绿茶叶和花中提取 TPS。过滤后，在相同温度下重复相同的提取过程。用这种方法获得的两种 TPS 的收率分别为 4.08% and和 6.88%, respectively, which were much higher than those obtained with hot water extraction under the same conditions (，远高于相同条件下热水提取的收率（分别为 1.28% and和 2.93%,）[ respectively) [38]. Compared to the conventional solvent extraction method, the enzymolysis extraction method has the advantages of a high extraction efficiency, strong specificity, and high extraction rate. In addition, it can reduce the environmental pollution caused by using a large amount of solvent and thus has broad application prospects. However, since the price of the enzyme is relatively high and its activity is affected by various factors, the extraction conditions for enzymolysis extraction must be strictly controlled to effectively obtain a higher extraction rate.
2.5. Other Extraction Methods
Some new methods for 38]。与传统的溶剂提取法相比，酶解提取法具有提取效率高、特异性强、提取率高等优点。此外，还可以减少因使用大量溶剂而造成的环境污染，具有广阔的应用前景。但由于酶的价格相对较高，其活性受多种因素影响，因此必须严格控制酶解提取的提取条件，才能有效获得较高的提取率。
6. 其他提取方法
除了上述常见的提取方法外，还报道了一些新的TPS extraction in addition to the above-mentioned common extraction methods have also been reported. For example, 提取方法。例如，Xu et al., optimized extraction conditions using a hydro/solvothermal method. They used high temperature and pressure (120 °C, 0.1 MPa) to infiltrate water into the tea leaves of Zhongcha 108 to destroy the cell structure, thereby separating TPS等人使用水/溶剂热法优化了萃取条件。他们利用高温高压（120℃，0.1MPa）使水分渗入中茶108茶叶中，破坏泡孔结构，从而分离出TPS[ [1].1 The extraction rate of crude polysaccharides obtained with this method was ]。该方法得到的粗多糖的提取率为4.7%, which was much higher than that of TPS obtained with ordinary hot water extraction, such as Ziyang green tea (3.46%)，远高于紫阳绿茶（3.46%）[ [22],22 Huangshan Maofeng tea (]、黄山毛峰茶（2.3%)）等普通热水提取得到的TPS。 [23],23 and]、祁门红茶 Keemun black tea (3.2%) [24].[ Sun et al., used alkali-assisted extraction to extract 24]。孙等人用碱辅助提取法提取茯砖茶多糖（Fuzhuan brick tea polysaccharide (FBTPS); the extraction conditions were a ）；萃取条件为 60 °C extraction temperature and a 萃取温度和 0.1 mol/L NaOH solution (溶液（pH = 10.0). Compared to hot water extraction, the yield of ）。与热水提取相比，碱提取 FBTPS by的产量对单糖组成和产量的影响更大[ alkaline30 extraction was found to have a greater impact on the monosaccharide composition and yield [30]. In addition, emerging extraction technology supercritical fluid extraction (]。此外，近年来新兴的提取技术超临界流体萃取（SFE) has also been used to extract）也被用于提取多糖。许多研究人员已经使用 polysaccharides in recent years. Many researchers have used SFE to extract various plant-derived polysaccharides, though there are still few applications of this process for TPS extraction. Chen et al., extracted TPS with a SFE 提取各种植物来源的多糖，尽管这种工艺在 TPS 提取中的应用仍然很少。Chen 等人用 CO 2-based提取 TPS基于 SFE method,方法，他们确定了该方法在 and they determined the optimum parameters of this method in TPS extraction as a particle size of TPS 提取中的最佳参数为粒径 380 μm, 20% absolute ethanol, an extraction pressure of 、20% 无水乙醇、提取压力 35 MPa, an extraction temperature of 45 °C, an extraction time of 2 h, which enabled a TPS extraction rate of up to 92.5%. Moreover, the TPS obtained with、提取温度 45 ℃、提取时间 2 h，TPS 提取率高达 92.5%。此外，用这种方法获得的 TPS 具有显着的生物活性 [ this31 method was]。尽管 significantly bioactive [31]. Although the SFE method is impressive, manageable, efficient, and environmentally-friendly, it is still not as common as other extraction methods in practical applications due to its expensive and time-consuming equipment. In addition, 方法令人印象深刻、易于管理、高效且环保，但由于其昂贵且耗时的设备，在实际应用中仍不如其他提取方法普遍。此外，Li et al.,等人发现通过阴离子反胶束系统萃取具有传质快、选择性高、成本低等优点 [ found that extraction via a anionic reverse micelle system exhibited the advantages of a fast mass transfer, high selectivity, and low cost [32]. In short, various auxiliary methods for 32]。总之，TPS extraction are able to improve the bioactivity of polysaccharides, shorten extraction times, and improve extraction yields.提取的各种辅助方法能够提高多糖的生物活性，缩短提取时间，提高提取得率。
